MIGHTYMOUSE

iTrader: (59)

just changed from my ooold delphi 96# (flow tested to about 94.x#)

to smp 120's from racetronix.

after a day of tuning i have logs reporting that these injectors are flowing consistanly low.. like low low.. like they are flowing LESS than my 96ers.

all things else being equal I would like to know WTF.

happy to update with data in any which way requested.

thanks.

onfire

iTrader: (17)

Just to give you some data to compare to:

Same 120's here.

BS3 log shows 1050lbs/hr total flow around 15ms at 6900rpm with a base pressure of 52psi.

MIGHTYMOUSE

iTrader: (59)

comparably i am at 543 fuel flow at 13.5# boost (56 fuel psi total) 10.2ms @ 56.6% DC 6700rpm

my injector opening time is set to .87ms and my injector flow rate is set to 1200

MIGHTYMOUSE

iTrader: (59)

just made a pull with a .88 injector delay and changed the flowrate from 1200 to 1100.

there was no magic that happened

onfire

iTrader: (17)

Tested on a flowbench:

55psi static = 131lbs/hr x 10.5 = 1378 for BS3....adjust to your base pressure...should be around 1226 for your pressure

13.9v = 0.33 actual offset fired with BS3 parameters.

If 1226 and 0.33 offset doesn't work for you....something is wrong with the injectors, regulator not 1:1, pump(s) weak or not on, etc. etc...

Good luck. I hate gremlins

MIGHTYMOUSE

iTrader: (59)

ok hold the phone, where did you get .33 from? that blows my numbers out the water!

onfire

iTrader: (17)

"Tested on a flowbench"

MIGHTYMOUSE

iTrader: (59)

Well that's a huge enough difference ill have to give it a try tomorrow! Im having a hard time figuring how ill get it to idle but imma try

onfire

iTrader: (17)

Are they working better?

MIGHTYMOUSE

iTrader: (59)

rained yesterday, going to give it a shot this eve.

racetronix sent me an 'interim' opening time suggestion of about .45ms at 13.9v


wish i actually ran at that much, my car is normally around 13.0 (.515ms they said to try)

but in general it is all far in the other direction of my current setting

MIGHTYMOUSE

iTrader: (59)

doing something with your injector phase angle? mine starts at 320 and drops by 20 per cell. ( i have no idea where this data originally came from)

onfire

iTrader: (17)

JM told me to leave the PA as is unless I used really big injectors that caused a very low DC. So I just use what came in the box.

MIGHTYMOUSE

iTrader: (59)

well that **** didnt work at all

the higher i moved the flowrate (from 1100 to 1250) the leaner it got (makes sense)

the lower i moved the opening time (from .9 to .3) the leaner it got (makes sense)

if i did let it try to run it would command about .4% duty cycle (or .5ms pulse) as it stalled out. (makes sense) (this was at 1200cc/min and .4ms open time)

putting the stuff back the way i had it base pulse comes up to about .9ms and 1% duty cycle. (makes sense) and everything with the idle is hunky dory. but falls way short in a hurry when you start pouring on the power.

(reasonable idle is about 38psi fuel pressure)

it all seems not not only not to improve but vastly move me in the wrong direction???

happy to send my files to anyone who wants to take a gander.

NicD

iTrader: (7)

Yup it all makes sense, the voltage offset is going to make the most difference at the smaller pulsewidths and not much of a difference at WOT so I wouldn't worry too much about getting that dialed in for now since it sounds like your big problem is that they aren't flowing as much up top as the 95lb injectors you had before.

It sounds like it's riding the minimum pulsewidth of the injector not opening and misfiring so to speak if it's stalling out, in that case just keep raising the offset a bit until it doesn't do it anymore. I do believe that in the BS3 the voltage offset effectively sets the minimum pulsewidth so you want to make sure it's high enough to prevent the injector from "misfiring".

This is the part I am wondering about, you have verified fuel pressure holds steady or rises appropriately and doesn't fall off with boost? As long as the fuel pressure does what it's supposed to I don't see how the injector isn't flowing what it's supposed to. I had the 120s from Racetronix in my car before and they did what they were supposed to. When I pulled them and put in the FIC 1200cc injectors everything lined up as I would expect comparison wise.

onfire

iTrader: (17)

Did you add VE after you reset 1200 and 0.4? Fooling the cc and ms should only crutch a wrong VE table. I have more cubes which makes it easier to tune the idle...idles around 14.2 : 1 at 54psi base.

Your 543lbs at 6700 at 56%DC compares to the 96's at ????

MIGHTYMOUSE

iTrader: (59)

no progress to report other than i verified my wideband is accurate and the pumps are holding pressure fine.

as an acid test i loaded my 96# file with the 120's in it and it ran pretty much fine.. within 5% or so i'd say.. (this is a WTF)

MIGHTYMOUSE

iTrader: (59)

why would i need to do that? the ve should be around 0 to 100% fuel reguardless of injector size.

the injector size should scale everything within reason such as not 30% off

onfire

iTrader: (17)

In a perfect world...yes.

But with BS3 I set the injector constants based on taking an injector and having it flow tested with the BS3 P&H parameters and set the slope to what that injector actually does at the voltage/FP from the bench.

And I have always had to fiddle with the VE down low to get the correct idle.

If those injectors are +- 5% from the 96's....then they are 96's....

MIGHTYMOUSE

iTrader: (59)

i just drove the car around with some low boost passes with on 96# tune. its definitely within 5%

so now what do i do? send both sets of injectors somewhere to get flowed???

i am pretty sure unless i pay to have some concrete data on these injectors that racetronix will not consider taking them back.

Meemperor

iTrader: (3)

What is your voltage @ the injector? The bigger ones are really finnicky with the amount of power they're getting and they may be only flowing as a 95# if you're only giving them like 8-9 volts. Before sending injectors away, I personally would check the voltage/amps at the injector. I know a few of my friends have Racetronix 120#'s in their cars with absolutely no problems. (Although they are running stock GM computer or AEM EMS)